Search results
Results from the WOW.Com Content Network
In chemistry, an acid–base reaction is a chemical reaction that occurs between an acid and a base.It can be used to determine pH via titration.Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.
The fourth row, labeled E, is the sum of the first two rows and shows the final concentrations of each species at equilibrium. It can be seen from the table that, at equilibrium, [H +] = x. To find x, the acid dissociation constant (that is, the equilibrium constant for acid-base dissociation) must be specified.
Brønsted and Lowry characterized an acid–base equilibrium as involving a proton exchange reaction: [18] [19] [20] acid + base ⇌ conjugate base + conjugate acid. An acid is a proton donor; the proton is transferred to the base, a proton acceptor, creating a conjugate acid.
On the other hand, if a chemical is a weak acid its conjugate base will not necessarily be strong. Consider that ethanoate, the conjugate base of ethanoic acid, has a base splitting constant (Kb) of about 5.6 × 10 −10, making it a weak base. In order for a species to have a strong conjugate base it has to be a very weak acid, like water.
Note that, if reactants and products were in standard state ... Acid–base equilibria: acid dissociation constant, hydrolysis, buffer solutions, indicators, ...
The equilibrium constant for the protonation of a base, B, + H + ⇌ + is an association constant, K b, which is simply related to the dissociation constant of the conjugate acid, BH +. = The value of is ca. 14 at 25 °C. This approximation can be used when the correct value is not known.
[5] [6] [7] In the Brønsted–Lowry theory acids and bases are defined by the way they react with each other, generalising them. This is best illustrated by an equilibrium equation. acid + base ⇌ conjugate base + conjugate acid. With an acid, HA, the equation can be written symbolically as:
The E and C parameters refer, respectively, to the electrostatic and covalent contributions to the strength of the bonds that the acid and base will form. The equation is -ΔH = E A E B + C A C B + W. The W term represents a constant energy contribution for acid–base reaction such as the cleavage of a dimeric acid or base. The equation ...